Before updating database, we can go to database
InitialPeopleCreator, rename it to InitialPeopleAndPhoneCreator
and add example phone numbers for example people (We renamed
InitialPeopleCreator.cs to InitialPeopleAndPhoneCreator.cs):

We added two phone numbers to Douglas, one phone number to Isaac. But if
we run our application now, phones are not inserted since this seed code
checks if person exists, and does not insert if it already exists.
Since we haven't deployed yet, we can delete database
(or remove entries from people table) and re-create it.

Now, we are running our application to re-create database and seed it.
You can check database to see PbPhones table and rows.